Sprinkler irrigation has over the years replaced many other forms of irrigation methods because it minimizes erosion, prevents many drainage problems, does not require land leveling, and provides light application of moisture for irrigating crops.
Whenever a sprinkler system is referred to by name, the reference is usually made to the manufacturer's brand name. Sprinkler systems are typically classified by the degree of their portability. For example, there are permanent systems, fully portable systems which can be moved from one field to another, and semi-portable systems where the piping is movable but the pumping plant is in a fixed location.
A number of manufacturers currently provide fittings for sprinkler systems. These fittings include, for example, couplers, "L" and "T" shaped pipe connectors, reducers, T-type valves for maintaining hydrants, and valve-opener elbows. Such fittings typically appear every 20 to 40 feet along portable sprinkler laterals and, therefore, enable ready identification of the system's manufacturer.
In some respects, the couplers, as well as other fittings of existing systems possess similar characteristics. For example, most have either one or two replaceable rubber gaskets to prevent the loss of water between the pipe and the coupler when pressure is applied. Nearly all of these gaskets are made to permit water to drain out whenever the line is shut off and the pressure is released.
There are some differences, however, in the way the couplers of different manufactures fasten to a pipe. Some have a latch, others are bolted or welded and still others have one end rolled or pressed into the pipe. On most systems, the coupler makes a flexible joint which allows the sprinkler pipe to bend or form an angle with respect to the coupler. Some flexibility is desirable, particularly on rolling land.
Most couplers also have a guide or guard apron that helps to keep dirt from being scooped up when the pipe is inserted, or moved.
Current use of aluminum pipe couplers for sprinkler lines has evolved into several popular styles, including so-called "drop lock" or "no-latch" couplers and "tow line" or "drag line" couplers. These couplers are fitted with one of two styles of Chevron gaskets: a "drain" gasket which, at a predetermined pressure drop, is designed to leak water through the coupler and a "non drain" gasket which leaks water at a substantially lower pressure. A typical locking mechanism for existing couplers is a latch or band bolted or welded to the male end of a piece of aluminum tubing. Sprinkler pipe fittings are also normally fabricated from cast aluminum or galvanized steel. There are several manufacturers of these fittings, the basic styles of which have been in use since at least as early as 1970. For instance, a representative coupler may be provided with a 3/4" or 1" female iron pipe thread to facilitate the installation of a metal (usually galvanized steel) riser of about 6" to 36" in length for supporting and delivering fluid to sprinklers of varying sizes.
This sprinkler-riser-coupler-aluminum tubing combination is light in weight and is commonly referred to as "hand movable" pipe. Such a system may be manually installed and removed, typically by about three individuals. The "drag line" or "tow line" styles can be pulled by tractor or machinery but it is necessary to manually install and disassemble the systems by two or more individuals.
In either towable or hand movable irrigation systems, the sprinkler coupler member may be provided with laterally projecting wings such as those described in U.S. Pat. No. 5,511,826. The purpose of such wings is to stabilize the coupler member, and thus protect the riser and sprinkler from damage, as the coupler is drawn along the ground. That is, the wings prevent "riser flop", i.e., rolling of the coupler member forwardly or rearwardly, during transport of the coupler member which might otherwise expose the riser and/or sprinkler to damage should the sprinkler impact the ground. Existing stabilizing wing designs, however, provide limited impact protection to the coupler member itself.
Existing towable or hand movable irrigation pipe coupler members also have an upwardly projecting, internally threaded, riser connection for threadably receiving the lower end of an externally threaded, sprinkler riser pipe. Among the deficiencies of current internally threaded riser connector designs is that the threaded connection can lose its sealing effect relatively soon after installation. As such, water may drain from the connection after the water supply is shut off, thereby causing water to pool in large areas and volumes around the coupler member. Such circumstances are disadvantageous in terms of water conservation and crop damage.
An advantage exists, therefore, for an irrigation pipe coupler member including means for protecting the coupler member from excessive impact damage as the coupler member is moved along the ground surface.
An further advantage exists for an irrigation pipe coupler member including means for enabling quick connection and disconnection of a sprinkler riser which minimizes water waste and crop damage.